Fuse housing construction utilizing extruded terminals and process for making same

ABSTRACT

An electrical fuse structure having electrically conducting Tshaped terminals. Two T-shaped terminals are disposed in spaced portions of an electrically insulating box-shaped fuse housing subsection so that part of the top or cross bar portion of the Tshaped terminal is positioned between an internal set of ribs and an inner portion of a housing subsection end wall. A similar fuse housing subsection is disposed over the remaining part of the top portion of the T-shaped member to enclose it. The housing subsections are secured in a complementary arrangement by bolts or rivets disposed in appropriate holes in the two subsections. The two subsections are thus joined to form a completely enclosed box in which the cross bar portions of the terminals are securely enclosed within the box at either end thereof, and with only the vertical or stem portions of the T-shaped terminals extending outwardly through openings in the ends of the box. Sand or other pulverulent arc quenching material is introduced into the inner chamber of the fuse housing through a hole drilled in the cross bar portion of one terminal which communicates with the inner chamber of the box and with the outside of the fuse housing through a suitable aligned opening in the fuse housing. After sand has been introduced into the fuse housing, the hole is sealed with a suitable plug. Fuse elements extend between the enclosed bar portions of the terminals within the enclosed chamber of the fuse housing. Ther fuse elements are surrounded by the pulverluent sand or crystalline material.

United States Patent [191 Blewitt et al.

[ Aug. 13, 1974 FUSE HOUSING CONSTRUCTION UTILIZING EXTRUDED TERMINALS AND PROCESS FOR MAKING SAME [75] Inventors: Donald D. Blewitt, Pittsburgh; Frank L. Cameron, Irwin; Charles H. Vondracek, Murrysville, all of Pa.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22 Filed: Feb.14, 1973 21 Appl. No.: 332,460

Primary Examiner- J. D. Miller Assistant Examine rFred E. Bell Attorney, Agent, or Firm-M. J. Moran [57] ABSTRACT An electrical fuse structure having electrically conducting T-shaped terminals. Two T-shaped terminals are disposed in spaced portions of an electrically insulating box-shaped fuse housing subsection so that part of the top or cross bar portion of the T-shaped terminal is positioned between an internal set of ribs and an inner portion of a housing subsection end wall. A similar fuse housing subsection is disposed over the remaining part of the top portion of the T-shaped member to enclose it. The housing subsections are secured in a complementary arrangement by bolts or rivets disposed in appropriate holes in the two subsections. The two subsections are thus joined to form a completely enclosed box in which the cross bar portions of the terminals are securely enclosed within the box at either end thereof, and with only the vertical or stem portions of the T-shaped terminals extending outwardly through openings in the ends of the box. Sand or other pulverulent arc quenching material is introduced into the inner chamber of the fuse housing through a hole drilled in the cross bar portion of one terminal which communicates with the inner chamber of the box and with the outside of the fuse housing through a suitable aligned opening in the fuse housing. After sand has been introduced into the fuse housing, the hole is sealed with a suitable plug. Fuse elements extend between the enclosed bar portions of the terminals within the enclosed chamber of the fuse housing. Ther fuse elements are surrounded by the pulverluent sand or crystalline material.

10 Claims, 7 Drawing Figures FUSE HOUSING CONSTRUCTION UTILI ZING Y EXTRUDED TERMINALS AND PROCESS FOR MAKING SAME BACKGROUND OF THE INVENTION This invention relates to fuse structures in general, and it relates in particular to simplified fuse structures employing extruded terminal portions and joinable housing subsections.

Prior art fuse structures comprise tubular, electrically insulating housings of curvilinear cross sections in the construction of the overall fuse and close toler- .7

ance of fuse parts is required. In prior art fuses, the'terminals are formed in the shape of electrically conducting disc-shaped'members with grooves in one face thereof. On the other face thereof is brazeda blade portion upon which electrical connections with an external circuit may be made. One of the thus constructed terminal sections then has a hole placed in it communicating between the two faces of the disc. Another hole is then drilled in each of the blade portions where electrically conducting external circuit leads may be attached to the blade portion by bolting. Radial holes are disposed circumferentially in the disc portion. Two of the thus formed terminal members are placed in a manufacturing jig in a spaced grooved face-togrooved face relationship so that the grooved face of one terminal is opposite the grooved face of another terminal with the blade sections of the two terminal members extending away from each other. While in the special jig, electrically conducting fuse elements are disposed between the two grooved faces of the spaced terminal members by soldering the ends of the fuse elements into the grooves in each face of the terminal members'The assembled portion is then transferred from the manufacturing jig in which it has been formed to aspecial jig wherein a cylindrical electrically insulating, hollow complete tubular housing member is slid over both the disc portions of the terminals sequentially to form a generally cylindrical tubular fuse structure having electrical terminals at either end thereof and electrical fuse elements enclosed within tubular housing members. The housing member has circumferential holes drilled therein at the ends thereof which must align with the previously drilled radial holes in the circumferential periphery of the terminals or holes may be drilled in both items at the time of assembly with the aid of special jigs and tooling. Pins are then disposed in the aligned holes in the housing and in the terminals to secure the housing to the terminals. Sand or pulverulent material is then introduced into the inner chamber of the fuse housing to surround the electrically conducting fuse elements therein. The fill holes are then plugged or sealed and the fuse structure is completed.

The structure of the overall fuse previously described and the process for making it have certain disadvantages. First the number of operations necessary to form a finished fuse housing is relatively large. Second, the degree of skill required to assemble the fuse is relatively complicated, i.e., the radial drill holes in the disc and in the electrically insulating tube typically have a spacing tolerance of plus or minus 0.003 inches and an angular tolerance of plus or minus 15 minutes. Accura cies of this magnitude can only be maintained by using special and expensive fixtures. It would therefore be advantageous to provide a fuse structure having less parts, requiring less tedious and expensive construction steps in the formation thereof, without sacrificing electrical efficiency and structural integrity and strength.

SUMMARY OF THE INVENTION 7 In accordance with the invention, a simplified relatively inexpensive electrical fuse assembly is disclosed having a minimum of component parts which do not require close tolerance and which may be formed without the need for extraordinary or unusual skill. In the present invention, the terminals for the fuse are formed from an extruded cast a powdered metal T-shaped electrically conducting material, such as copper. The T- shaped terminal sections eliminate theneed for brazing a blade upon a disc as in the prior art. The vertical portion of the T-shaped terminal as normally viewed comprises the blade while the horizontal or bar portion of the 'T-shaped terminal as normally viewed comprises the portion of the terminal to which the fuse elements are secured within the fuse. A molded housing section is disclosed which comprises generally planar rectangular shaped surfaces. More specifically, each subsection of the housing looks like a rectangular box having a bottom, side portions and end portions but not top portion. The end portions terminate lower at the upper ends thereof than the side portions. Both the end portions and side portions intersect the common bottom. The side portions have on the top edges thereof complementary locking channels. That is, one side portion contains a groove in the upper end thereof and the other side contains a complementary raised portion. The interlocking shapes are disposed in the subsections in the molding process which is used to form it. Consequently, if a subsection is reversed and turned around, the groove therein will align with the raised portion of a similar subsection and similarly the grooved portion of the last-mentioned subsection aligns with the raised portion of the complementary subsection which is fitted thereto. The use of the two subsections together forms an enclosure having no open areas to the outside thereof other than the openings formed by the gaps at either end between complementary portions. The end portions are not as high as the side portions of the boxes. Spaced inwardly from the inside of the end portions of the complementary subsections are rib sections which may be vertically oriented in the preferred embodiment. The distance between the rib sections and the inner portions of the ends of the subsections are generally equal to the width of the top of the previously described extruded terminal members so that the T bar members may be inserted therebetween and securely,

" nalare inserted, one at'each end, into the space between the inner portion of the end wall and the ribs of the housing subsections. The previously applied fuse elements are flexible and may bow or bend slightly as thetwo T bar sections are inserted in the respective channels between the ribs and the end portions. Once these terminals and the fuse elements therebetween are in place in one housing subsection, a complementary housing subsection is disposed in place over the remaining T bar portions of the extruded terminal members in a reverse fashion so that the grooved portion of one edge of one subsection aligns with the complementary edges of the housing subsection in which the T bar members have already been disposed. When thus disposed or assembled, the internal portion of the housing is entirely enclosed with-only the fill hole in the T bar section of one terminal communicating between the chamber and the outside environment. In addition, only the blade portions extend through the walls of the housing. Thecomplementary housing subsections are riveted or bolted or otherwise secured together through convenient holes provided in the side thereof. Sand or pulverulent material is then introduced into the internal portions of the housing for arc quenching and the fill hole is sealed with a plug. The fuse construction as completed forms an electrically conducting fuse member capable of providing all of the electrical properties of the prior art fuse structures and which has the additional advantage of being more simply constructed without the need of placement pins between the electrically conducting fuse terminals and the housing members.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention reference may be made to the preferred embodiment, exemplary of the invention, shown in the accompanying drawings in which:

FIG. 1 shows a view, in elevation, of a complete fuse structure partially cut away for convenience of illustratron;

FIG. 2 shows an end view of the fuse structure shown in FIG. I;

FIG. 3 shows an elevation of the terminals and electrical fuse elements therebetween which are used in FIG. 1;

FIG. 4 shows an end view of the terminal construction shown in FIG. 3;

FIG. 5 shows a top view of a terminal and fuse element structure similar to that shown in FIG. 3;

FIG. 6 shows a sectional view of the fuse construction shown in FIG. 5 at sectional lines VIVI;

FIG. 7 shows an orthogonal view of one fuse housing subsection.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and FIG. 1 in particular, a'view of the fuse structure 10 is shown. Fuse structure 10 includes a fuse housing 12 of which there are two parts or sub-housings or housing subsection 12a and 12!). In the preferred embodiment of the invention, the housing 12 may comprise glass-polyester electrically insulating material. The housing subsections 12a and 12b may be formed by molding the glass polyester material into the desired shape which will be more specifically described when referring to FIG. 7. It is to be noted that where desired the glass polyester material may be pigmented before or during the molding operation, such as with red pigment to provide a red fuse housing 12. It is to be understood that even though molding may be the preferred means for making the fuse housing 12, any method which is suitable for providing an electrically insulating structure 12 may be employed. As part of the fuse housing subsection 12b, a top view of the vertical rib sections 14 is shown. Similar vertical rib sections are present in subsection (not shown) and in other locations in housing subsections 12b which are not shown in FIG. 1. Rib section 14 comprises generally vertical protrusions extending inwardly from the side walls 15 of the fuse housing subsection 12b. Also shown in FIG. 1 is a portion of an end wall 16a for housing subsection 12a, it being understood that a similar end wall (not shown) is present at the other end of housing subsection 12a. End wall 16a includes therein a slot or opening 18a, the purpose of which will be described in detail more fully later herein. Fuse structure 10 includes therein two electrically conducting terminal members 20 and 20a. Terminal members 20 and 20a may be generally considered to be structurally alike with the exception of an opening in terminal member 20 which will be described herein later.

Terminal members 20 and 20a when viewed from the bottom of FIG. 1 are generally in the shape of a T. This will be move fully appreciated with reference to FIG. 5. Electrically conducting terminal 20 includes a top or section of wider cross sectional area 22 which may be considered the cross bar or top horizontal portion of the T, as viewed in the normal position. This may be referred to as the T-bar section. Terminal 20 may also include a blade or terminal section 24 which appears as the vertical portion of a T, as viewed in the normal position. In a preferred embodiment of the invention, the T-shaped electrically conducting terminals 20 and 20a comprise powdered copper which has been sufficiently compressed, homogenized and bonded in a convenient manner to be molded or extruded into or through a T- shaped die to form an extruded or molded section or bar stock of electrically conducting material. After the bar stock of T-shaped extruded material has been cut into convenient lengths for use as terminals 20 and 20a in fuse structure 10, one terminal has drilled therein a feed or fill hole 26 which communicates with both the top and bottom of the horizontal T bar when viewed in the normal T position or said in another way which communicates with both the right and left side of electrically conducting portions 22 of terminal member 20 of FIG. 1. A similar hole may be provided in terminal 20 a but in a preferred embodiment is omitted or is not therein provided, it being understood that only one feed hole 26 is necessary to provide material into the inner portion of fuse housing 10. Fill material 28 such as sand or other pulverulent material may be provided through feed hole 26 in a completely constructed fuse assembly 10.

It is to be understood that the sand or pulverulent materisl 28 need not be present in all embodiments of the invention but that in those embodiments of the invention in which the sand 28 is present, it provides the normal characteristics of pulverulent material in electrically conducting fuses. That is, it cooperates with the heat of a fused fuse element to form a fulgurite which aids in arc extinction in fuse operation.

Also, disposed on or against one wall side or section of T bar 22 are two exemplary fuse elements 30. These fuse elements are connected in a similar manner to a similar wall portion (not shown) of terminal 20a to normally provide electrical continuity between terminals 20 and 20a. it is to be understood that the shape, length and disposition of the fuse elements 30 between terminals 20 and 20a as shown in H0. 1 or representative of a preferred embodiment only and are not limiting. Fuse elements such as 30 may be disposed in any convenient manner between the electrically conducting portions of terminals 20 and 20a as shown in FIG. Ti.

On the upper edges of side walls T5, as viewed in FIG. 1, are disposed interlocking means 32b and 34b. Interlocking means 321; comprises a generally V-shaped groove cut downwardly along the entire length of and into the upper edge of wall 115. Interlocking means 34b comprises complementary similarly shaped triangular protrusions arising from the upper edge of the other side wall of housing lZb. Housing secton 112a which is a duplicate of or identical to housing section 1121) has similar protrusions and grooves cut therein and by orienting the disposition of housing 12a the complementary grooves and protrusions may be aligned in a complementary manner when joining housing subsection 12a with housing subsection 12b to form a complete housing section 12. This will be better understood by reference to FIG. 2, where the complementary characteristics and disposition of the grooves and protrusions are more easily shown. in addition to the complementary grooves and recesses 32b and 34b respectively, the vertical rib sections 114 have disposed thereon a raised portion 36 similar to raised portion 34b and a complementary opening or hole 38 in the other rib 114 of the other side wall i5. (Ionsequently, when housing subsection 12a is mated or joined to housing subsection 12b, the raised protrusion 3b? in one side wall 15 fits into complementary hole or recess 38 in the other side wall 15 of housing subsection 1121). Similar raised portions and recesses are provided in other portions of housing subsections 112a and i219 (not shown). The orientation of the grooves or recesses 32b and 38 in wall 15 and the raised portions 34b and 3d, respectively, in the other wall provide a firmly secured joint when the two sections llIZa and 1212 are joined or assembled, as previously described. The longitudinal orientation of the protrusion 34!; and the recess 32b prevent transverse sliding or disengagement of the two subsections 112a and 12b of the fuse housing The transverse interlocking members 36 and 38 prevent longitudinal sliding or disengagement of the housing subsections 12a and 12b. Subsections 12a and 12b have U-shaped grooves or openings 40 therein in which holes 42 which extend downwardly into the side walls 15. When the fuse housing subsection 112a is combined with the fuse housing subsection 112b, a rivet or bolt 44 may be fed through the holes 42 and secured at the other end thereof to complete the joining of subsection 12a to subsection 12b. In a preferred embodiment, member 44 comprises a 1.968 inch long stainless steel rivet having a AISI-305 characteristic.

It is to be understood with respect to the fuse element 30, shown in W6. 11, that in a preferred embodiment of the invention, the total length of the fuse element is 1.734 inches. The thickness of a fuse element is 0.01

inches and the width thereof is 0.25 inches. The fuse element 30 may comprise a strip of silver material adapted to be soldered at the ends thereof to the primarily copper T bar section 22. The fuse element 30 in the preferred embodiment includes five sets of notches therein having an angular displacement of 36 which are spaced axially from each other at the apex thereof at 0.25 inches. Each set is spaced so that complementary slots 45 are separatedby' 0.03 inches of fusible material. It is also to be understood that the feed hole 26 may have a plug 33 for sealing purposes disposed therein after the filling of the inner chamber of the fuse structure 10 with pulverulent material 28. In a preferred embodiment, plug 33 comprises soft copper which is between 0.52 inches and 0.82 inches in length and which is between 0.205 inches and 0.210 inches thick or as measured on a diameter thereof. It is also to be understood that ribs 14 comprise locating ribs against which one surface of T bar section 22 rests in a completed fuse assembly. The blade sections 24 and 24a of each terminal member 20 and 20a respectively, have disposed therein on longitudinal centers of 4.062 inches in a preferred embodiment, mounting holes 27 which are useful for connecting terminals from external or electrically conducting circuits to the fuse structure 10.

Referring now to FIG. 2, an end view of the structure 110, as'shown in FIG. 11, is shown. It can be seen that the two fuse housing subsections 112a and 12b are joined in a complementary manner so that protrusion 34a in fuse housing 12a conveniently joins or interlocks with groove or recess 32b in fuse housing 12b. In a similar manner, raised portion or triangular portion 34b in fuse housing subsection 12b substantially aligns with the interlocks with groove or recess 32a in housing subsection 120. Grooves or U-shaped openings 18a and 18b are disposed in a complementary relationship in the end walls 16a and 16b of housing subsections 12a and 12b of fuse structure 10 respectively. A portion of the underside of T bar section 22 of terminal 20 can be seen through the openings 18a and 18b. Hole 26 which in this embodiment of the invention is disposed on the left side of blade 24 of terminal 20 has been scaled by the sealing plug 33. In another embodiment of the invention, the hole 26 may be on the other side of blade 24, that is in the region of U-shaped opening 18b. The complementary grooves or recesses 32b and 32a may be considered as sealing grooves, for in addition to providing relatively secure interlocking of housing sections 112a and 12b when they are joined to form a unitary housing structure 10, the cooperation of the sealing grooves 32b and 32a with their respective counterparts or interlocking members 32a and 32b in the other housing subsections provides a relatively good seal to prevent sand and small pulverulent matter from shifting out of the inner chamber of housing 10. In a completed fuse housing structure 10, glue or a similar cement or bonding material 46 is provided in the recesses 18a and 18b to completely seal the end portion of the housing structure 10 and to seal the housing along the edges of the subhousing assemblies.

Referring now to FIG. 3, a partially assembled fuse section is shown comprising two complementary and similar terminal members 20 and 20a such as shown in FIG. 1 and electrically conducting fuse elements 30 disposed therebetween. In a preferred embodiment of the invention, the end portions of fuse elements 30a and 30b may be soldered on or to terminals 20 and 20a. The previously described notches 45 are shown disposed in the electrically conducting sections of fuse material 30a and 30b. In a preferred embodiment, the shortest distance between any sections on the two terminal members 20a and 20b is generally 1.67 inches.

Referring now to FIG. 4, and end view of the assem bly shown in FIG. 3 is shown in which the terminal member 20 is shown having the feed or fill hole 26 therein disposed to the left of blade portion 24 in T-bar or cross portion 22. With respect to FIGS. 1, 2, 3 and 4, the electrically conducting terminal members 20 and 20a may be considered as combination terminals and sealing members because of the dual characteristics of each member of providing electrical continuity, and of concurrently sealing the internal portion of the housing 10 at the ends thereof.

Referring now to FIG. 5, another view of the partial assembly including the fuse elements and terminal sections is shown. The T-shaped characteristics of the terminal members and 20a are best exemplified or shown in this view. An extrusion die having the shape of the T-shaped sections 20 and 20a, as shown in FIG. 5, through which the material of the terminals is forced during an extrusion process is acceptable or suitable for producing the shape of terminals 20 and 20a. The previously described blade member 24 is shown in a side view and the cross bar section 22 is shown as connected thereto. It will be noted that both terminals 20 and 20a look like the standard letters T tilted on their sides in respectively different directions or orientations. If they are both rotated 90, the one on the left counterclockwise and the one on the right counterclockwise, the characteristic T-shape is evident. It can be seen that the blade section 24 represents the long vertical section of the T and the cross bar section 22 represents the top portion cross bar portion or T bar portion of the T shaped terminal. It can be seen the grooves 50, 50b, 50c, 50d; and 50a, 50:2, 50fand 503 are cut into or positioned respectively in the associated terminal members 20 and 20a so that terminal fuse elements 3%, and d, and 30e can be disposed between the terminals 20 and 20a, and soldered thereto, in the respective grooves thereof to form a relatively secure electrical connection between terminal 20 and terminal 20a. The holes 1 27 are shown in each of the two terminal sections 20 and 20a. It is the cross bar sections (22 and 22a of terminals 20 and 22a respectively which are disposed between the inner surfaces of the ends 16 and 16a respectively of the assembled housing sections 12 and the vertical rib portions 14. This secure affixing of the electrically conducting portions 22 and 22a in the housing assembly 12 provides for a fuse assembly 10 which does not require the use of pins to interconnect the housing assembly 12 to the electrically conducting terminals 20 and 20a. The single feed hole 26 is shown in the cross bar section 22 of terminal 20. By closely examining the electrically conducting fuse sections 30a, 30c, 30d and 30e it can be seen that they are bowed a distance 54 in the middle in the axial center thereof. This bowing allows for slight variations in the distance between the two terminal portions 20 and 20a during assembly and for contraction and expansion of the fuse elements dur ing temperature excursions during operation of the fuse.

Referring now to FIG. 6, a cross sectional view taken along line VI-VI of FIG. 5 is shown. In this case, the

disposition of the fuse elements is shown in an ordered array. On the left it can be seen that the fuse elements 30b, 30g, 30f and 30e are disposed in a vertical row in the appropriate grooves 50, 50b, 50c, 50d respectively and on the right it can be seen that three fuse elements 30a, 30c and 30d are disposed in the same grooves 50, 50b, and 500 but spaced from the previously described fuse element 50, 50b, 50c and 50d. One of the important features shown in FIG. 6 is that two or more fuse elements may be spaced in the same groove. The feed hole 26 is also shown in FIG. 6.

Referring now to FIG. 7, an orthogonal view of a fuse housing subassembly 12b is shown, it being understood that subassembly 12a is the same as subassembly 12b. Subassembly 12b comprises a pair of elongated vertically disposed walls and a pair of transverse shortened spaced parallel walls 16a which intersect the walls 15. The fuse subassembly has a bottom, base or wall which intersects walls 15 and walls 16a. Disposed along the upper edge 15a of one wall 15 is a riased triangularly shaped interlocking member 34b. Member 3412 has vertical holes 42 therein which transverse the entire vertical height of wall 15. Each wall 15 has on the inner portions thereof two vertically oriented rib members 14 one in the rear and one in the front. Rib members 14 adjacent to edge 15a of wall 15 have raised interlocking portions 36 thereon. The other wall 15 has an upper edge 15y into which is cut an interlocking groove 32b which is generally complementary in shape to the raised portion 34b so that, if the subassembly 12b were rotated and placed on top of a similar subassembly the protrusions therein would align with the grooves of the other subassembly 12b and vice versa. There are rivet holes 42 provided in the last named wall 15 similar to the rivet holes in the other wall 15. A pair of vertically oriented rib sections 14 are also disposed along the inner surface of that wall 15 with the upper edge 15y. In this case, there are grooves or recesses 38 in the upper portion of ribs 14 which are complementary to raised portions 36 in the other rib portions 14. As mentioned previously, the complementary relationship of the raised portions 36 and the lowered or recessed portions 38 assist in joining the complementary equal subhousing assemblies 12b together. The front most rib assemblies 14, as viewed in FIG. 7, each has a leading edge 68 in both cases which is relatively falt or planar. The rearmost rib assembly 14, as viewed in FIG. 7, has a similar edge 65 which is also relatively flat and which I faces the back portion of the fuse housing subassembly 12b. In fuse housing subassembly 12b, the two relatively short, spaced end walls 56 and 58 have inner surfaces 66 and 64, respectively. In addition end wall 58 has cut therein a U-shaped groove or recess 18b. During assembly of the fuse assembly 10, the cross bar portions 22a of the terminal member 22 as shown in the preceding figures fit between the surfaces 68 of the ribs 14 and the inner surfaces 66 of front end 56 and are securely held in place therebetween. In a similar fashion, T bar section 20a of the other assembly 20, the one having the hole 26 in it for the fill material 28 fits between the surfaces 65 of the rear ribs 14 and the inner surface 64 of wall 58, in such a manner that the hole 26 is aligned with opening 18b.

In a preferred embodiment of the invention, the width of a subassembly housing, such as 12b, is generally two inches and the height of the side walls 15 thereof exclusive of the interlocking portions is generally one inch. The thickness of the end walls and the side walls is generally 0.25 inches and the horizontal distance between the edgeof a side wall and the apex of a triangular interlocking portionsuch as 34b and 32b is 0.125 inches. In the preferred embodiment, the distance between the centers of the adjacent rib portions 14 is 1.528 inches along wall 15 and the distance between the centerlines of the rib portions and the nearest end subassembly 12b is 0.572 inches. The length of an entire subassembly 12b is genrally 2.67 inches. The distance between centers along a wall 15 of the holes 42 is 1.17 inches with the difference between the same centerlines and the next adjoining end portions of an end wall being 0.75 inches. The center of hole or opening 18b is 0.703 inches above the bottom most part of the base 70 and the radius of curvature of the bottom portion of the U-shape hole 18b is 0.156 inches. The height of the raised protrusion along edge lu.0f wall 15 is 0.109 inches and the base of the raised protrusion which is triangular in shape is 0.047 inches from either edge of wall 15. The length of the transverse protrusions 36 on rib 14 is 0.216 inches. In a preferred embodiment, the base 70 and the side walls 15 and the end walls 56 and 58 join to form an inner chamber 60 which chamber is completely sealed when two subsections 12a and 12b are joined together with the previously described terminals in place and with the hole 26 plugged. In a preferred embodiment of the invention, the electrically insulating material comprising the molded housing subsection 12b is red glass-polyester material.

It is to be understood that the electrical rating of the fuse is independent of at least certain aspects of the structure of the fuse assembly 10. It is also to be understood that the shape of any fuse element between the terminals 20 and 20a need not be exactly as shown in FIGS. 1 and 3 but may be spiral, ribbed, circular or have any other suitable shape for conducting electrical current between two terminals and fusing or blowing at appropriate overload conditions. It is to be understood further that additional rib sections 14 may be provided along the inner surfaces of walls if additional structural support is necessary or desired. It is also to be understood that the triangular complementary shape of the sealing grooves and protrusions is not limiting and that other shapes may be employed where desired including shapes which are not complementary but which provide for the use of gaskets between the various housing subsections. It is also to be understood in some embodiments of the invention, that more than two subsections may be employed in constructing the fuse housing and that in other embodiments of the invention, housing subsections may be ganged lengthwise to form longer fuses. It is also to be understood that the shape of the subsections may be such that multiple protective circuits may be enclosed in a single fuse housing unit.

The teachings of the present invention have many advantages over the prior art. One of the important advantages is in the reduction of the number of structural elements necessary to form an overall fuse structure. Another advantage lies in the ease of which the fuse structure may be fabricated and constructed. Other advantages lie in the obviation of the necessity of high tolerances between the various parts of the fuse elements. Another advantage lies in the fact that prior art complicated manufacturing process for constructing the fuse and the relatively complicated jigs necessary to construct the fuse may be avoided. Another advantage lies in the fact that an entire terminal may be formed from a single extruded piece of material thus obviating the need for soldering various terminal portions together. Another advantage lies in the face that the end portion of terminal portion of the fuse may perform dual functions: namely, providing the electrical continuity to the fuse element and sealing the end of the fuse. Another advantage lies in the fact that the relatively rectangular planar angular shape of the overall fuse structure allows for more convenient storing, fabrication, delivery and installation than the round tubular shaped fuses of the prior art Another advantage lies in the .fact that should one fuse housing subsection be found defective for some reason during the manufacturing process or after the fuse has been installed the defective portion may be replaced without moving the entire fuse or without unnecessarily wasting the other subsection which has not been damaged or is not defective. Another advantage lies in the fact that the position of the sealing grooves and assembly holes are provided by the molding process whereby the fuse housing is cori structed thus obviating the need for drilling. Another advantage lies in the fact that the manufactureing nameplate and operating characteristics may be molded into the fuse housing at the time the fuse housing is formed.

What we claim as our invention is:

l. A fuse structure. comprising: an electrically insu lating fuse housing having a central chamber therein, an inner portion of which is of predetermined cross sectional area, said fuse housing having a first opening therein which is relatively smaller in cross sectional area than said inner portion and which communicates with said central chamber, said fuse housing having a first raised protrusion on the inner surface thereof which protrudes into said central chamber and which is spaced from said first opening;

a combination electrically conducting terminal member and sealing member having one portion thereof which is larger in cross-sectional area than said first opening, said one portion of said combination terminal and sealing member being disposed in said central chamber and securely fixed therein between said first raised portion and that portion of said central chamber which is adjacent said first opening, said combination terminal member and sealing member having a terminal portion thereon which extends through said first opening to communicate with a first region not within said central chamber and which is spaced from said fuse housing to thereby provide electrical continuity be tween said central chamber and said first region, said combination terminal member and sealing member also providing a seal for said first opening in said housing;

a second electrically conducting terminal member, a

second opening in said housing, said second terminal member communicating with a second region not within said central chamber which is spaced from said fuse housing, said second terminal also communicating with said central chamber through said second opening, said second opening being spaced from said first opening;

a fusible element disposed between said second electrically conducting terminal member and said first 1 1 electrically. combination terminal member and sealing member in said central chamber; and

pulverulent material disposed within said central chamber around said fusible element to form a fulgurite when said fusible element fuses, said pulverulent material being retained within said central chamber independent of the orientation of said fuse housing.

2. The combination as claimed in claim 1 wherein said fuse housing comprises a plurality of similarly shaped joined fuse housing subsections.

3. The combination as claimed in claim 1 wherein said second electrically conducting terminal member is of the same general dimensions as said first combination terminal member and sealing member, wherein said second opening has the same general dimensions as said first opening, wherein said housing member has a second raised protrusion on the inner surface thereof which protrudes into said central chamber and which is spaced from said second opening, and wherein said second combination terminal member and sealing member cooperates with said second opening, with the portion of said fuse housing therearound and with said second raised protrusion in to be secured in said central chamber between said latter portion of said fuse housing and said second raised protrusion.

4. A fuse structure, comprising:

an electrically insulating fuse housing having a central chamber therein, an inner portion of which is of predetermined cross-sectional area, said fuse housing having a first opening therein which is relatively smaller in cross sectional area than said inner portion and which communicates with said central chamber, said fuse housing having a first raised protrusion on the inner surface thereof which protrudes into said central chamber and which is spaced from said first opening, siad fuse housing comprising a plurality of similarly shaped joined fuse housing subsections, each of said subsections having complementary interlocking portions thereon which fit together when the subsections have been joined to provide the fuse housing;

a combination electrically conducting terminal member and sealing member having one portion thereof which is larger in cross-sectional area than said first opening, said one portion of said combination terminal and sealing member being disposed in said central chamber and securely fixed therein between a portion of said housing around said first opening and said first raised protrusion, said combination terminal member and sealing member having a terminal portion thereon which extends through said first opening to communicate with a first region not within said sealed chamber which is spaced from said fuse housing to provide electrical continuity between said central chamber and said first region; said combination terminal member and'sealing member also providing a seal for said first opening in said housing;

a second electrically conducting terminal member in said fuse housing, a second opening in said housing, said second terminal member communicating with a second region not within said central chamber which is spaced from said fuse housing, said second terminal also communicating with said central chamber through said second opening, said second opening being spaced from said first opening;

a fusible element disposed between said second electrically conducting terminal member and said first combination electrically conducting terminal member and sealing member in said central chamber; and

pulverulent material disposed within said central chamber around said fusible element to form a fulgurite when said fusible element fuses, said pulverulent material being retained within said central chamber independent of the orientation of said fuse housing.

5. The combination as claimed in claim 4 wherein the number of said subsections is two.

6. A fuse structure, comprising:

an electrically insulating fuse housing comprised of a pair of complementary elongated fuse housing subsections, each of said subsections being opened on one side thereof, said one portion of said section adjacent said open the thereof having a raised locking portion thereon, another portion of said subsection adjacent said open side thereof having a lowered locking portion thereon, each said subsection having a transverse lip portion adjacent either end thereof, first and second transverse rib members spaced inwardly of said ends, said subsections cooperating to form a generally enclosed central chamber when said subsections'are joined at said opened sides, a portion of said housing being of predetermined cross-sectional area, said fuse housing having at the ends thereof first and second openings therein which are relatively smaller in cross-sectional area than said inner portion and which communicate with said central chamber, said first and second openings being between complementary lip portions on either end of said fuse housing;

a pair of combination spaced electrically conducting terminal and sealing members each having one portion thereof which is larger in cross-sectional area than said first and said second openings, said one portion of one of said combination terminal and sealing members being disposed in said central chamber and securely fixed therein between said first opening and said first transverse rib members the other of said combination terminal and sealing member being disposed in said central chamber and securely fixed therein between said second opening and said second transverse submember, each said combination terminal and sealing member having a terminal portion thereon, one said terminal portion extending through said first opening to communicate with a first region which is disposed away from said chamber and which is spaced from said fuse housing to provide electrical continuity between said central chamber and said first regions, the other said terminal portion extending through said second opening to communicate with a second region which-is disposed away from said chamber and which is spaced from said fuse housing to provide'electrical continuity between said central chamber and said second region, each said combination terminal andsealing member also acting to seal said first and second openings respectively in said housing;

a fusible element disposed between said first and said second spaced electrically conducting terminal and sealing members in said central chamber; and

pulverulent arc quenching material disposed within said central chamber around said fusible element to form a fulgurite when said fusible element fuses, said pulverulent material being retained within said central chamber independent of the orientation of said fuse housing.

7. The combination as claimed in claim 6 wherein said housing comprises polyester material.

8. The combination as claimed in claim 6 wherein said combination terminal and sealing members comprise solidified powdered copper material.

9. The combination as claimed in claim 6 wherein said elongated subsection comprises:

a rectangularly shaped planar base;

a first pair of generally equal rectangularly shaped spaced parallel planar sides transversely disposed upon said base and extending along the length of said base;

a second pair of generally equal rectangularly shaped spaced parallel planar side transversely disposed upon said base and extending along the width of said base, said first and said second pairs of planar sides having common points of intersection, said second pair of sides extending a shorter distance from said base in said transverse direction than said first pair of sides;

one said side of said first pair of sides having at the edge thereof furthest from said base a raised interlocking portion;

the other said side of said first pair of sides having at the edge thereof furthest from said base a lowered interlocking portion complementary in shape to said raised portion so that two of said elongated members may be joined at said complementary interlocking portions to form a completed housing. 10. A process for making an electrical fuse comprising the steps of:

extruding electrically conductive material in an extrusion means to form an elongated terminal blank having a section large in cross section and a section relatively smaller in cross section;

cutting said elongated terminal blank transversely to said length to form two combination terminals and sealing members;

molding electrically insulating material into two complementary similar fuse housing subsections having inner transverse ridges therein and lips spaced around two opposite ends thereof;

forming a hole in one said terminal member in the region of the largest cross section;

attaching a fuse element between said larger sealings of said combination terminal and sealing means;

positioning said portion of one said combination terminal and sealing member into each end of one of said fuse housing subsections between said ridge nearest that end and said lips at that end;

positioning the other said housing subsection in engagement with said last mentioned housing subsection and said combination terminal and sealing members placed therein to form a completed housing assembly having the samller section of said terminal members extending outside of said housing and having said fuse element enclosed within said housing;

filling said fuse housing with pulverulent material through said hole in one said terminal member, and sealing said hole. 

1. A fuse structure, comprising: an electrically insulating fuse housing having a central chamber therein, an inner portion of which is of predetermined cross sectional area, said fuse housing having a first opening therein which is relatively smaller in cross sectional area than said inner portion and which communicates with said central chamber, said fuse housing having a first raised protrusion on the inner surface thereof which protrudes into said central chamber and which is spaced from said first opening; a combination electrically conducting terminal member and sealing member having one portion thereof which is larger in cross-sectional area than said first opening, said one portion of said combination terminal and sealing member being disposed in said central chamber and securely fixed therein between said first raised portion and that portion of said central chamber which is adjacent said first opening, said combination terminal member and sealing member having a terminal portion thereon which extends through said first opening to communicate with a first region not within said central chamber and which is spaced from said fuse housing to thereby provide electrical continuity between said central chamber and said first region, said combination terminal member and sealing member also providing a seal for said first opening in said housing; a second electrically conducting terminal member, a second opening in said housing, said second terminal member communicating with a second region not within said central chamber which is spaced from said fuse housing, said second terminal also communicating with said central chamber through said second opening, said second opening being spaced from said first opening; a fusible element disposed between said second electrically conducting terminal member and said first electrically combination terminal member and sealing member in said central chamber; and pulverulent material disposed within said central chamber around said fusible element to form a fulgurite when said fusible element fuses, said pulverulent material being retained within said central chamber independent of the orientation of said fuse housing.
 2. The combination as claimed in claim 1 wherein said fuse housing comprises a plurality of similarly shaped joined fuse housing subsections.
 3. The combination as claimed in claim 1 wherein said second electrically conducting terminal member is of the same general dimensions as said first combination terminal member and sealing member, wherein said second opening has the same general dimensions as said first opening, wherein said housing member has a second raised protrusion on the inner surface thereof which protrudes into said central chamber and which is spaced from said second opening, and wherein said second combination terminal member and sealing member cooperates with said second opening, with the portion of said fuse housing therearound and with said second raised protrusion in to be secured in said central chamber between said latter portion of said fuse housing and said second raised protrusion.
 4. A fuse structure, comprising: an electrically insulating fuse housing having a central chamber therein, an inner portion of which is of predetermined cross-sectional area, said fuse housing having a first opening therein which is relatively smaller in cross sectional area than said inner portion and which communicates with said central chamber, said fuse housing having a first raised protrusion on the inner surface thereof which protrudes into said central chamber and which is spaced from said first opening, siad fuse hOusing comprising a plurality of similarly shaped joined fuse housing subsections, each of said subsections having complementary interlocking portions thereon which fit together when the subsections have been joined to provide the fuse housing; a combination electrically conducting terminal member and sealing member having one portion thereof which is larger in cross-sectional area than said first opening, said one portion of said combination terminal and sealing member being disposed in said central chamber and securely fixed therein between a portion of said housing around said first opening and said first raised protrusion, said combination terminal member and sealing member having a terminal portion thereon which extends through said first opening to communicate with a first region not within said sealed chamber which is spaced from said fuse housing to provide electrical continuity between said central chamber and said first region; said combination terminal member and sealing member also providing a seal for said first opening in said housing; a second electrically conducting terminal member in said fuse housing, a second opening in said housing, said second terminal member communicating with a second region not within said central chamber which is spaced from said fuse housing, said second terminal also communicating with said central chamber through said second opening, said second opening being spaced from said first opening; a fusible element disposed between said second electrically conducting terminal member and said first combination electrically conducting terminal member and sealing member in said central chamber; and pulverulent material disposed within said central chamber around said fusible element to form a fulgurite when said fusible element fuses, said pulverulent material being retained within said central chamber independent of the orientation of said fuse housing.
 5. The combination as claimed in claim 4 wherein the number of said subsections is two.
 6. A fuse structure, comprising: an electrically insulating fuse housing comprised of a pair of complementary elongated fuse housing subsections, each of said subsections being opened on one side thereof, said one portion of said section adjacent said open the thereof having a raised locking portion thereon, another portion of said subsection adjacent said open side thereof having a lowered locking portion thereon, each said subsection having a transverse lip portion adjacent either end thereof, first and second transverse rib members spaced inwardly of said ends, said subsections cooperating to form a generally enclosed central chamber when said subsections are joined at said opened sides, a portion of said housing being of predetermined cross-sectional area, said fuse housing having at the ends thereof first and second openings therein which are relatively smaller in cross-sectional area than said inner portion and which communicate with said central chamber, said first and second openings being between complementary lip portions on either end of said fuse housing; a pair of combination spaced electrically conducting terminal and sealing members each having one portion thereof which is larger in cross-sectional area than said first and said second openings, said one portion of one of said combination terminal and sealing members being disposed in said central chamber and securely fixed therein between said first opening and said first transverse rib members the other of said combination terminal and sealing member being disposed in said central chamber and securely fixed therein between said second opening and said second transverse submember, each said combination terminal and sealing member having a terminal portion thereon, one said terminal portion extending through said first opening to communicate with a first region which is disposed away from said chamber and which is spaced from said fuse housing to provide electrical continuity between said central chamber and saiD first regions, the other said terminal portion extending through said second opening to communicate with a second region which is disposed away from said chamber and which is spaced from said fuse housing to provide electrical continuity between said central chamber and said second region, each said combination terminal and sealing member also acting to seal said first and second openings respectively in said housing; a fusible element disposed between said first and said second spaced electrically conducting terminal and sealing members in said central chamber; and pulverulent arc quenching material disposed within said central chamber around said fusible element to form a fulgurite when said fusible element fuses, said pulverulent material being retained within said central chamber independent of the orientation of said fuse housing.
 7. The combination as claimed in claim 6 wherein said housing comprises polyester material.
 8. The combination as claimed in claim 6 wherein said combination terminal and sealing members comprise solidified powdered copper material.
 9. The combination as claimed in claim 6 wherein said elongated subsection comprises: a rectangularly shaped planar base; a first pair of generally equal rectangularly shaped spaced parallel planar sides transversely disposed upon said base and extending along the length of said base; a second pair of generally equal rectangularly shaped spaced parallel planar side transversely disposed upon said base and extending along the width of said base, said first and said second pairs of planar sides having common points of intersection, said second pair of sides extending a shorter distance from said base in said transverse direction than said first pair of sides; one said side of said first pair of sides having at the edge thereof furthest from said base a raised interlocking portion; the other said side of said first pair of sides having at the edge thereof furthest from said base a lowered interlocking portion complementary in shape to said raised portion so that two of said elongated members may be joined at said complementary interlocking portions to form a completed housing.
 10. A process for making an electrical fuse comprising the steps of: extruding electrically conductive material in an extrusion means to form an elongated terminal blank having a section large in cross section and a section relatively smaller in cross section; cutting said elongated terminal blank transversely to said length to form two combination terminals and sealing members; molding electrically insulating material into two complementary similar fuse housing subsections having inner transverse ridges therein and lips spaced around two opposite ends thereof; forming a hole in one said terminal member in the region of the largest cross section; attaching a fuse element between said larger sealings of said combination terminal and sealing means; positioning said portion of one said combination terminal and sealing member into each end of one of said fuse housing subsections between said ridge nearest that end and said lips at that end; positioning the other said housing subsection in engagement with said last mentioned housing subsection and said combination terminal and sealing members placed therein to form a completed housing assembly having the samller section of said terminal members extending outside of said housing and having said fuse element enclosed within said housing; filling said fuse housing with pulverulent material through said hole in one said terminal member, and sealing said hole. 